ShowyEdge for Mac helps multilingual users discern the current keyboard language by coloring the top of the screen in a user-selected color. It's designed to run in the background and has no main window, only a preferences screen. Some options that stand out are the ability to choose the color for each language, to apply a different color to every third of the line, to make the line transparent, and to launch the utility on startup.
ShowyEdge lacks a menu bar icon. Even its dock icon is turned off by default. When you launch the app for the first time, you are presented with the preference window, which lets you add the currently used language to the list and apply colors to the three sections on top of the screen. You can also adjust the width of the colored line, change its opacity, or choose to automatically run the utility on startup. Overall, ShowyEdge for Mac accomplishes what it sets out to do without consuming many resources.
If you're a multilingual user who often types in different languages, ShowyEdge for Mac can help you easily identify the active keyboard language. It's useful for people who work in fullscreen mode, where the menu bar with the country's flag is hidden from view by default. But if you use only English, this app has nothing to offer you.